Study on Ultra-Long Dam Vertical Deformation Monitoring Method Based on GPS

This paper mainly focuses on GPS height data processing method for deformation.The ellipsoidal height accuracy is improved by optimizing various error correction and accurate calculation models of high precision GPS analysis software and selecting solution parameters in GPS data processing.The GPS monitoring result is appraised by the second-order leveling surveying.We found that the mean square error of difference value between GPS monitoring deformation and the second-order leveling surveying deformation is less than 1mm,and there is a smaller systematic error between the ellipsoidal height deformation and the second-order leveling deformation,whose value is about 0.5 ～ 1mm;however,this system error does not affect the outcome of vertical deformation monitoring.The conclusion is drawn that the GPS monitoring can replace precise leveling in ultra-long dam vertical deformation monitoring in plain region.